jkmcafee

Have an 85 GSL-SE that has been sitting for years. Replaced the fuel tank, fuel pump and fuel filter. Mechanic says fuel is pumping to engine, but will not start. He suspects injectors.

He disconnected fuel lines and put fuel directly into engine (not sure how) and it runs so long as he keeps putting fuel in it.

Wanted ideas as to how to further troubleshoot. The mechanic is a friend of my brother and am not sure he has much experience with these engines.

Any ideas would be helpful. Are the injectors susceptible to sticking after sitting up for years? Any way to loosen them up? Any suggestion for replacements?

mazdaverx713b

iTrader: (91)

If it's been sitting for that amount if time i would also suspect the injectors to be clogged with gummed up fuel. You can send them out to have them cleaned and flown tested. I've freed injectors myself and it can be done but the best option is to contact a company like witch hunter.

WJM ROTARIES

It is common for injectors to seize up if sitting for a long period.Have them tested and serviced

jkmcafee

Thank you... Is there a good way to loosen them up, just to get it running just to verify there isn't any other issues, like relay issues, etc. that would prevent fuel from getting to the engine?? Regardless, plan to have them serviced. Just ready to get it running!!

GSLSEforme

Sitting for years,how many?
Mazda fuel pump or aftermarket? Some of aftermarket pumps don't play well with SE fuel system...can the fuel pump be heard running while engine is cranking?
Doubtful your mechanic put fuel lines directly into engine,fuel needs to be atomized for engine to start and continue to run. The only way to introduce combustible mixture into engine is into throttle body and for that to be possible,the air intake hose needs to be removed from throttle body. The air flow meter below air cleaner relies on air being pulled thru it by engine during cranking and running to close contacts in it to allow fuel pump to run. Air intake hose disconnected,no fuel pump.
What he very likely did was spray carb cleaner or throttle body cleaner into throttle body while someone else cranked and started engine and then continued to spray into throttle body to keep running.

The basic part of fuel system your mechanic is dealing with is no different than fuel injection on a piston engine-they're both internal combustion engines. Injectors work the same way. Regarding "loosening"injectors up,i have done this with carb cleaner,compressed air and an injector pulser that applies current to injector coil in preset and adjustable milliseconds to open and close the pintle in injector. Without the above combination,any type of success is unlikely,even with this equipment,more failure than success...as a professional,time is money and this effort is not cost effective.

As far as replacing injectors with new,non Mazda units are available,even reman are available. However even though parts store computer/salesman says they have something identical to what's in the car,they don't KNOW that and selling you an injector that isn't the same calibration will result in a no start or flooding/poor driveability once engine is running,not to mention a lot of what is available ranges from poor quality to junk. Tearing apart the engine twice to replace such injectors will have you using up all your bad words.Years of experience talking.My advice,and i strongly recommend you follow it,is to remove and send your injectors out for cleaning and testing like others have mentioned. Go on witchunter.com websiteand see about the particulars.I have used them many times,turnaround time is @ a week.

Once you begin to disassemble engine to access injectors, carefully disconnect injector connectors. They are rather delicate,again,your mechanic should be familiar with how to remove them without damage. They have been cooked where they live for35+ years and are known to be the source of poor engine performance complaints from corroded terminals/wiring in connector. Another piece of advice...once disconnected,test each one with a Noid light to be certain ecu is triggering injector while cranking. If a steady flash is not visible on both,stop disassembling at this point and find where the fault is. If you skip this step,you could be disassembling/assembling engine in vain,putting in your freshly cleaned injectors with still a no start. The Noid light is THE tool to use for testing,use of other types of testlights are a gamble as the injector driver in ecu is not meant to handle the load of anything more than injector and damage to the 35 year old ecu is possible and you will not find one of these at parts store or Mazda dealer.Your mechanic should know what a Noid light is and have them. They come in sets to fit the various connectors on many makes of cars. They can be rented at many auto parts stores. If you need to see what a Noid light looks like,i can post a picture of one.
Consider replacing rubber fuel lines to and from injector fuel rail and the lines that come up firewall and go to engine.
Will look in on your thread for further posts

jkmcafee

Thank you for the through post. We will go down the path you recommended.

The fuel talk and fuel pump are both Mazda OEM - cost me about a grand for both. Didn't want to cheap screw those. Will share this with the mechanic. He did mention that the fuel lines were cleaned out from the talk all the way up to the engine, and the fuel pump is working. How sensitive is the engine to actual fuel pressure?

The troubleshooting hints are very helpful - I was looking for a way to test the electrical part of it, just to make sure the ECU was working. I will look up the noid light. Sounds like the ECU is expecting a high impedance load at the injector, so I definitely understand the issue with putting instrumentation or a light on it that may draw too much current. I'm a EE, so even though I've never worked on injectors, I certainly understand electrically the points that were made.

Before we disassemble then engine... is there a good way to tap into those same signals somewhere else on the car without disassembling the engine, as a way to quickly check that the ECU signals to the injectors are being generated? I realize that the wiring could be broken in-between, but am thinking out loud about a way to maybe non-intrusively check as much as I can BEFORE the mechanic disassembles the engine. We plan to disassemble anyway, but I was just curious.

Again, very thankful for your comments.

jkmcafee

Sorry, didn't answer the first question... It has been sitting for probably 7 years or so. The story behind the car... I bought it right out of college in '86 as the second owner. It was my present "from me, to me" since I'd put myself through school. I sold it to my hometown neighbor in '90 after I married and bought my first truck. Regretted the deal, so I bought it back in roughly '95. Kept it running and started slowly restoring the interior back when Mazda parts were still available. Move the car to my parents shop in '06, and at that time had the engine, including the injectors, cleaned and serviced. Would go home on holidays, crank the car and drive it just to keep it going. But about 7 years ago, it failed to start because of a battery issue. That just snow balled because I had a sick daughter (cancer patient) so I just let it go. But there were no major issues, and the car really hasn't been driven regularly since the mid 90's. It's in great shape except for the paint. The car is very special to me, and my wife thinks I'm an idiot - but I've got to get this thing running again. I didn't mind spending the extra $$ on Mazda OEM parts because I want to keep it. I am sure those who have owned and loved these cars understands.

jkmcafee

I am not sure what happened - still getting used to the user interface, but it looks like my first attempt to reply got lost...

Thanks for the thorough post. We will go down the path you suggested. Understand the steps and I understand the importance of using something that doesn't cause excessive current draw from the ECU. That is the kind of guidance I was looking for.

But, before we disassemble the engine, would it make sense to tap into the same electrical signals with the noid light, just to make sure the injector is working? I realize wires could be broken in between the ECU and injectors, and we can re-test, but I am just wondering if this "baby step" may make sense to you. I am only asking because it may be nice to make sure the ECU is working before he does the tear down and potentially causes another issue.

We plan to service the injectors as you recommended. Just thinking out loud about a way to non-intrusively test the ECU, so I don't run into swap-a-tronics with the mechanic. Especially given the ECU is a precious commodity.
t run

H

GSLSEforme

Using OEM parts in fuel system was a smart decision,potentially avoided fueling issues there.
Again,should replace all rubber fuel lines due to age and incompatibility with ethanol fuel. Fuel injection rated hose and FI hose clamps.

There is no real easy way to tap into injector circuit,testing at the ecu can be done. This involves pulling pass side door sill molding and pull carpet back to expose plate ecu is mounted underneath and removing it to access ecu. A bit of work to do this.
Suggest you test at injectors,testing here will test ecu and complete harness.
You have to disassemble to get to them,so....
If the injector connectors need to be replaced,I can give you a part #.
These cars have a simple robust fuel system and short of rodent damage to wiring,if the car ran ok before,it will again. Testing ecu signal to injectors is really to prevent tearing engine apart twice to check this in event engine doesn’t start you know this is not the problem and look elsewhere for the fault.

Understand your attachment to your car,i’ve owned my
SE for 26 years. I think this particular model has the best of the best and was the flagship of 1st gens in two years it was produced.

LongDuck

Just throwing this out there that I use a Mechanics Stethescope (like a doctor would use to listen to your heart, but has a long metal rod on the end) to listen to specific parts of the car. For Fuel Injectors, you can thread the rod down through the Upper Intake Manifold and put the end of the rod on top of the Fuel Injector to listen to it with the engine running. The stethescope ear plugs will tun out the other engine noises, and Fuel Injectors sound like "ticktickticktickticktick" at idle, increasing with throttle.

This would quickly tell you whether they're firing. As to whether they're flowing properly, you can't tell that unless they're sent out for cleaning / servicing / flow-balancing.

It's a good quick test, and once you own a mechanics stethescope, you'll find a lot of uses around vehicle diagnostics in the future, and they only cost about $10-12.

jkmcafee

Thanks for the input. I do not live near the mechanic but I happened to think about something... is it possible that the fuseable link that I used to use to "un flood" the engine could be disconnected and controlling power to the injectors?

What does that fuseable link control? Fuel Pump, Injectors, Coils, all of the above??

Rotary Alkymist

I'd like to add that fuel injectors are so simple to clean. I'm honestly astounded why so many people send them out. It seems like a waste of time and money.

GSLSEforme

Injectors,ecu. Current for ignition coils,igniters supplied by ignition switch. Wire color at ignition coils is black/yellow. Fuselinks can be tested with test light.There are 5.




If you are keeping car indefinitely,consider replacing fuel hose from fuel rail to metal fuel lines attached to engine and from there to feed and return lines coming up firewall.Don't reuse oe spring clamps. Use FI rated fuel hose and FI hose compatible hose clamps,not worm clamps.
The id of original fee and return line hose is 8mm. You can use 5/16" hose to replace it
While fuel rail is removed to access injectors,clean it out with carb cleaner and lo pressure compressed air.

Before disassembling engine take pics of throttle/cruise control cables and note amount of free play each has and duplicate that on reinstall.Be careful with removing upper intake manifold so you don't break the vacuum hose spider beneath.You'll want to drain enough coolant from radiator to allow removal of coolant hoses to wax thermostat. Consider replacing these hoses also,likely hardened from age. One of the two is NLA but an FC coolant hose can be substituted.
A good idea to replace all vacuum lines on solenoid rack and rest of manifold while engine is apart. Just the process of manifold removal can cause vacuum hose undisturbed for 35 years to leak,you will find this out when trying to figure out why engine doesn't idle/run right as you take everything apart to chase the problem. Replace one hose at a time to avoid confusion. Use an exacto knife or single edge razor blade to slice hose along nipple and work the slice open and away from nipple with a pocket screwdriver to keep from putting stress on plastic parts that are NLA. Better to take your time doing this. Once hose is removed,use it as a template to cut a replacement length. A spritz of silicone spray into ends of hose will ease installation onto nipples to avoid breakage.

Resist the temptation to reuse gasket between upper and lower intake manifolds because it still looks good,best way to end up with a vacuum leak. While you can get this gasket aftermarket,best to use Mazda oe gasket #N304-13-116A. Can be ordered from any Mazda dealer or purchased from Atkins Rotary, Racing Beat or Mazdatrix which are vendors that cater to all generations of RX7. All have online stores and found on ebay. While you are on phone with folks at Witchunter verify whether they supply new upper/lower injector seals,if not source them from where you're getting your gasket from.

Once you have the fuel system back together and sealed up-before reinstalling upper intake,very good idea to pressurize fuel system and check for leaks as much easier to rectify any while engine still apart. There are a pair of connectors located by the air filter housing on right side of engine compartment. One is green and is used for adjusting throttle position sensor(TPS) which you may have to do on reassembly. There is a tool you can make to check and adjust. Some use leds. I use a pair of #74 dash light bulbs in the tool,believe they're 3.4 watts.
The other connector is black,its purpose is to run fuel pump without cranking engine to pressurize fuel system to check for leaks. A short jumper wire with 1/4" male spade terminals crimped on each end is inserted into each of terminals in connector and ignition key turned to run position runs fuel pump. Don't be tempted to start or drive car with this connector jumpered as it circumvents several fail safes that shut fuel off in event of an accident. Its only purpose is to energize fuel pump to test fuel system integrity.

Go to foxedca.rx7manuals and download factory service manual. You'll need this for specifications,testing procedures and specific info pertaining to your year and model car.

Some pics of mentioned connectors and Noid Light set and TPS adjusting tool.

GSLSEforme

Definitely a waste of time trying to clean them yourself even with some tools on hand to facilitate doing so "consistently" with any numbers of injectors.

How many sets of injectors have you cleaned with your simple method and how successful? I submit that having cleaned enough sets with proper tools to cycle injector on/off at different frequencies to clean them i have had many that couldn't be cleaned with this method and needed to be cleaned ultrasonically with professional equipment. I also submit to you,those injectors you cleaned to satisfactory performance would perform even better if professionally cleaned,balanced and flow tested,fact. That's why i send them out to be serviced as do many other professionals. There are three companies i deal with that give consistent results with printouts of before/after cleaning test results that clearly show the benefits of the service. None of these places would be in business for the length of time they have if everyone was able to clean their injectors themselves. The service costs considerably less than a set of oe quality injectors.

Rotary Alkymist

I'm sure they do run better, after all they did clean them. I simply let the car show me the result. If, after cleaning a suspicious injector the problem goes away indefinitely then that's good enough for me and probably good enough for most. I've cleaned a handful of injectors without any issues. I mean how many times does one find himself with an injector issue?
I'm not sure how well you want an injector to work haha. You might have a higher standard than me.

I imagine the difference is nominal unless your racing in which case you'd just change them out. Mind you I haven't encountered anything too grotesque in my experiences. Maybe one day I'll look at an injector and say to myself, "I should send these out to get cleaned professionally." Probably not though.

GSLSEforme

More often than you would think. Done this for a living many,many years.
The customer and I insist the vehicle runs 100%. Higher standard...
If you’re playing with your own cars,like you say,good enough.

jkmcafee

Thank you - I downloaded the manuals and am familiarizing myself with the fuel system. I really appreciate the time you spent to explain all this. I feel like I'm going in to this with a lot more confidence.

LongDuck

So keeping them in top running shape through professional cleaning (*and fuel filter changes...), is important. Even more so, as the SE only has one injector per rotor, so any mismatch in flow or spray pattern has a big effect on power and driveability. Its a small cost to benefit for professional cleaning,

GSLSEforme

jkmcafee,responded to your pm.

GSLSEforme

jk,any progress on your car?

jkmcafee

Good morning. I have been out of town for two weeks for work.

All of this is moving much slower than I had hoped, but I am trying to be patient. This guy is a friend of my brother. Mechanic plans to make one more pass through using the ether trick, then plans to remove the injectors.

I think you had mentioned a list of things to do, like changing out all the vacuum hoses, fuel line, etc. I will probably order all that is required so that I can send it to the mechanic.

I will keep you posted.

GSLSEforme

Hoping it works out for you.

jkmcafee

Success! Car is running again after about 10 years. Thanks for the great input from his forum (especially GSLEForme) - the input was invaluable. For the benefit of the forum I wanted to follow up with some of the details of what I did.

--> At this point we were not sure what was wrong. Car ran fine when put in the garage years earlier but family circumstances took priority and car was neglected.

First, I was trying to help diagnose and fix the car remotely. I'm in Florida and the mechanic is in Georgia so this presented a challenge that required baby steps along the way. With GSLSEForme's help, the plan was to keep it simple, solve one thing at a time, report back, and go to the next. Mechanic and I both had to learn how this car works so that we could think about (but not act upon) two steps forward. The service manuals and information provided by forum members really helped.

Inspection. Squirrels had gotten into the air intake. Removed air intake and removed nesting and food supply (pecans). Verified the air intake damper was moving freely.

Replaced Battery. Must do. Battery was dead and we weren't sure if squirrels had wiring harnesses as part of their diet. Luckily the electrical system seemed OK. Checked that fuses and fusable links were OK.

--> At this point were fairly certain the car would turn over but did not want to push any contaminants into the engine without clear fuel lines

Replaced Gas Tank - A heavily rusted fuel tank was replaced with an OEM tank. Not cheap, but I plan to keep this rare car forever (85 GSL-SE late model production car with '86 paint code 3A with leather interior) and bring her back to as close to the glory days as I can. I will keep you all posted. Lesson learned - proper fuel with tank full up to the neck helps avoid corrosion when storing.

Replaced Fuel Pump - Although probably not required I wanted to replace with an OEM fuel pump since I wanted to keep the car. Not cheap but see above.

Verified Clean Fuel to engine - Flushed lines up to fuel supply and verified fuel pump could supply fuel up to the fuel intake. Lesson learned - should have used fuel pump bypass plug to pressurize fuel system and check PSI.

Verified Engine would turn over - but engine would not start on its own.

Verified Ignition - Sprayed starting fluid into intake and verified engine would run as long as ether was being sprayed. Lesson learned - should have checked leading and trailing ignition at this time. As it turns out, trailing ignition controls injectors and drives tachometer. A quick glance at the tachometer at this time would have told us that the trailing ignition necessary for the injectors was working.

---> At this point we knew the engine was sound but the car would still not crank on its own. Injectors were suspected

Professionally cleaned Fuel Injectors - Called Witch Hunter but too busy to expedite injectors. They recommended Advanced Advanced Injector, 220 North Dexter, Valley Center, KS 67147. They did a great job and turned the injectors around quickly with a test report that showed that the injectors were partly stopped up and unbalanced. One was at 660 cc/min, one was at 690 cc/min. Both were cleaned, balanced at 700 cc/min, and leak free when returned.

Pressurized Fuel System - Reinstalled fuel injectors. Made the decision to replace pulsation damper, all fuel lines, vacuum lines, and coolant hoses while the plenum was off. Pressure regulator was not available or it would have been replaced too. Used test connector under the air intake to activate the fuel pump and pressurize the fuel system. Measured at 48 PSI.

Tested Injector Control Signal - Used noid light to test to make sure +12V and Injector control signal from the ECU were working for both injectors. Decided to replace the injector connectors based on the harsh environment and 35 year old connectors. Lesson Learned - replacing injector control connectors was a great idea. The contacts literally fell apart when replacing. It is hard to say, but this could have been part of the issue all along.

--> At this point we knew we had good fuel pressure, ECU control of the injectors, good ignition, and that the engine started with ether. So, had good confidence the car should run once the plenum was reinstalled.

Plenum was reinstalled. Car did not start at first but Ether was used again to get it primed. Finally, after lots of smoke and running rough at first, the car warmed up and with some idle adjustments it all settled out at 800 RPM. Will probably have to do finer adjustments but to have it running smoothly after all these years was great.

Can't tell you how excited we were to get it running. Just the first step in a restoration project that I will keep you all informed about. Next, we plan to replace all fluids, brake master cylinder and clutch master cylinder so I can drive it home.

Thanks again for all your support.

tallbozo

iTrader: (5)

Got any pics of the car?

LongDuck and GSLSEforme are Godsends for GSL-SE troubleshooting.

jkmcafee

https://www.rx7club.com/introduce-yo.../#post12378372

Learned recently car is a late 85 production (Apr 85) and had special 3A paint color.